UITableViewCells not displaying on screen after intercepting calls to UITableViewDelegate methods - ios

Question

While playing around with the iOS 7.1 SDK (on XCode 5.1.1), I am trying to intercept the calls to the delegate methods of UITableViewController by creating a class that implements the UITableViewDelegate and UITableViewDataSource protocol. I am expecting the tableView to delegate the calls to MyTableViewDelegate which does some customization and delegate back to HomeViewController.
Through debugging, I found tableView:cellForRowAtIndexPath: method and tableView:willDisplayCell:forRowAtIndexPath: of the HomeViewController, the drawRect: method of my custom UITableViewCell class was called, and the cells have right content. **So it seems to me that the cells are drawn to somewhere. But just not displaying on the screen (The table row divider lines were displayed on the screen though).**I wonder if anyone knows why it doesn't work. Below is the code snippet. Thanks in advance for your insights.
HomeViewController.h
// HomeViewController.h
#interface HomeViewController : UITableViewController <UITableViewDelegate, UITableViewDataSource> {
UITableViewController *tableViewController;
UITableView *tableView;
}
#property(nonatomic, strong) MyTableViewDelegate *myDelegate;
#end
HomeViewController.m
// HomeViewController.m
- (void)loadView {
[super loadView];
tableViewController = [[UITableViewController alloc] initWithStyle:UITableViewStylePlain];
[self addChildViewController:tableViewController];
[tableViewController didMoveToParentViewController:self];
myDelegate = [[MyTableViewDelegate alloc] init];
[myDelegate setDelegate:self];
tableView = [[tableViewController tableView] retain];
[tableView setFrame:[[self view] bounds]];
[tableView setAutoresizingMask:UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth];
[tableView setDelegate:myDelegate];
[tableView setDataSource:myDelegate];
[tableView setClipsToBounds:NO];
[[self view] addSubview:tableView];
}
- (UITableViewCell *)tableView:(UITableView *)table cellForRowAtIndexPath:(NSIndexPath *)indexPath {
MyEntry *entry = [self entryAtIndexPath:indexPath];
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cellClass"];
if (cell == nil) cell = [[[cellClass alloc] initWithReuseIdentifier:#"cellClass"] autorelease];
[self configureCell:cell forEntry:entry];
return cell;
}
MyTableViewDelegate.h
// MyTableViewDelegate.h
#interface MyTableViewDelegate : NSObject <UITableViewDelegate, UITableViewDataSource> {
}
#property (nonatomic, assign) id delegate;
#end
MyTableViewDelegate.m
// MyTableViewDelegate.m
#implementation MyTableViewDelegate
#synthesize delegate;
// Display customization
#pragma mark - Delegate
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
if ([delegate respondsToSelector:#selector(tableView:willDisplayCell:forRowAtIndexPath:)]) {
<...some customization ....>
[delegate tableView:tableView willDisplayCell:cell forRowAtIndexPath:indexPath];
}
}
...
// and all other required and optional methods declared by the UITableViewDelegate and UITableViewDataSource protocol.
EDITED:
if I set the delegate and dataSource of tableView to the HomeViewController instance rather than MyTableViewDelegate instance, it works just fine.
// HomeViewController.m
- (void)loadView {
[super loadView];
...
[tableView setDelegate:self];
[tableView setDataSource:self];
...
EDITED:
Normally we can just do all the work in HomeViewController. However, in my case, I am trying to see if it's possible to insert a layer between HomeViewController and tableView. I have a special use case where I would expect HomeViewController to not be able to override the customization implemented in MyTableViewDelegate (intended to be a library). Hence, it's not a good idea to implement MyTableViewDelegate as a base class and make HomeViewController derive from it.
As far as I can see, the only connection between the HomeViewController and tableView is that tableView is managed as a subView by HomeViewController and tableViewController is also a childViewController of HomeViewController. Would the additional layer (ie. MyTableViewDelegate) break this connection since MyTableViewDelegate delegates every method call back to HomeViewController? If so, how does it break? Again, without the MyTableViewDelegate layer, the above code works just fine.